MP2632 datasheet(27/37 Pages) MPS

27 / 37 page

MP2632

– ALL-IN-ONE, 3A SW CHARGER, 3A BOOST

MP2632 Rev.1.0

www.MonolithicPower.com

6/24/2016

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

VDP_SRC

VLGC_HI

IDP_SRC

CHG_DET

VDAT_REF

IDM_SINK

RDM_DWN

Figure 11: USB Port Detection

When the input source plugs in, the IC starts

DP1/DM1 detection. DP1/DM1 detection has two

steps: data contact detection (DCD) and primary

detection. DCD uses a current source to detect

when the data pins have made contact during an

attach event. The protocol for data contact

detection is as follows:



The power device (PD) detects if VBUS is

asserted.



The PD turns on DP IDP_SRC and the DM pull-

down resistor for 40ms.



The PD waits for the DP line to be low.



The PD turns off IDP_SRC and the DM pull-

down resistor when the DP line is detected to

be low, or when the 40ms timer expires.

DCD allows the PD to start primary detection

once the data pins have made contact. Once the

data contact is detected, the IC jumps to the

primary detection immediately. If the data contact

is not detected, the IC jumps to the primary

detection automatically after 300ms from the

beginning of the DCD.

Primary detection is used to distinguish between

the USB host (or SDP) and different types of

charging ports.

During primary detection, the PD turns on VDP_SRC

on DP1 and IDM_SINK on DM1. If the portable

device is attached to a USB host, DM1 is low. If

the power device is attached to CDP, DCP, or

another dedicated charging port, DM1 remains

high.

To be compatible with different capacities of the

input

source,

the

input

current

limit

recommended to be set using Table 2 if a 5V

input is requested.

Table 2: Input Current Limit Setting

DP1/DM1 Detection

IIN_LMT

Floating

500mA

SDP

500mA

CDP or DCP

Set through RILIM

The USB detection runs once VIN is detected and

is independent of the charge enable status. After

the DP1/DM1 detection is done, the IC sets the

input current limit as shown in Table 2.

When the detection algorithm is completed, the

DP1 and DM1 signal lines enter a high-Z state

with approximately 4pF of capacitive load.

External Input Current Limit Setting

The IC has a dedicated pin used to program the

input current limit when CDP or DCP is detected.

The current at ILIM is a fraction of the input

current. The ILIM voltage indicates the average

input current of the switching regulator as

determined by the resistor value between ILIM

and GND. As the input current approaches the

programmed input current limit, the charge

current is reduced to give priority to the system

power.

The

input

current

limit

threshold

can

determined with Equation (4):

ILIM

40(k )

(A)

(k )







(4)

Input Voltage Regulation in Charge

Mode

In charge mode, if the input power source is not

sufficient for supporting both the charge current

and the system load current, the input voltage

decreases.

the

input

voltage

internally

approaches the 4.65V input voltage regulation

threshold preset, the charge current is reduced to

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